Jefferson Lab Presentation to Teacher Education Program November 8, 2006. Subatomic Particles: What do we study at Jefferson Lab? Dr. Allison Lung 12 GeV Upgrade Project Director & Senior Staff Physicist. nucleons. Nuclear Physics: All About Atoms. education.jlab.org/atomtour.
Jefferson LabPresentation to Teacher Education ProgramNovember 8, 2006
What do we study at Jefferson Lab?
Dr. Allison Lung
12 GeV Upgrade Project Director
Senior Staff Physicist
Nuclear Physics: All About Atoms
All visible matter in universe is made of Generation I particles.
fundamental particles interact by responding to a force from another particle
Atoms are 99.999999999999% empty space !!
Atom: nucleus of neutrons & protons with orbiting electrons
go down one layer
Electron: very light particle with negative charge
Proton: weight equals ~2000 electrons, positive charge
Neutron: weight almost equal to proton, no net charge
go down one layer
Quarks: fundamental particles, 6 types,
up/down/strange are the lightest and most common
Forces: strong, electromagnetic, weak, gravity;
strong force holds quarks together
go down one layer ???
is there another layer ???
we are more “empty space” than matter,
“empty space” is filled with carefully balanced forces,
get students to expand on the solar system model of atoms
great Web pages for students:
great Web pages for teachers:
What forces hold the neutrons and protons together in an atom?
What forces hold the quarks inside a proton together?
How is electric charge distributed within a neutron or proton?
How is magnetic field distributed within a neutron or proton?
Does a “free” quark behave the same as a quark bound inside a proton?
Does a “free” quark behave the same as a quark bound inside a heavy atom?
Study how quarks and gluons combine to form
protons and neutrons
Study how protons, neutrons, and electrons combine to form atoms
~ $10 Million cost
~ 5 year construction
~ 5 year measurements
~ 50 ton weight
~ 20 feet height
How do strange quarks contribute
to the properties of the proton?
Do they contribute to the spin?
Are the strange quark’s electric
interactions different from their
Pentaquark – 5 quark combinations may exist?
proton can take many shapes……
quark’s spin doesn’t match neutron’s spin
Upgrade magnets and power supplies
6 GeV CEBAF
Two 0.6 GV linacs
New cryomodules get new rf zones
FUTURE JEFFERSON LAB
Note that tagger is
80 m upstream of
Electron Beam from CEBAF
for your students
physics is a great career !
Nuclear Physics as a Career